An Organic Light-Emitting Display (OLED) device is becoming a main development direction of new display device, due to advantages such as self-illumination, fast response, wide viewing angle and ability to be fabricated on a flexible substrate.
For an OLED product of high resolution, because a Pixels Per Inch (PPI) thereof is too high and the pixel requires a plurality of TFTs to serve as a compensation circuit, the pixel does not have sufficient storage capacitance. For example, the pixels are evaluated by a resolution of 8.5-inch WUXGA (2560*1600), and the pixel has the storage capacitance of only 50 fF in a common array technology. However, in order to maintain stability of a pixel voltage, a leakage current of 1×e−13 to 1×e−14 ampere is needed to maintain a voltage change of a grayscale in a frame time, and therefore, it is very important to increase the storage capacitance.